During an excursion to Central America, Beast and Jubilee come face to face with
- Adaptation Origin Connection: In the comics, the Hounds are slaves to the mutant-hunter Ahab, not followers of Apocalypse.
- Ascended Extra: Caliban had previously as an unnamed extra in previous episodes, not even as a member of the Morlocks.
- Balance Between Good and Evil: Apparently the reason why Apocalypse still exists. His body was destroyed, but his essence lingers in a void and waits for the chance to return.Cortez: Apocalypse cannot not exist.
- Bittersweet Ending: Beast, Jubilee, and Caliban escape, but Apocalypse manages to return.
- Cosmic Deadline: The followers can only restore Apocalypse if they place a sacrifice on the temple's altar during a celestial alignment.
- Crazy-Prepared: Apocalypse had Cortez organize the Hounds and wait at his remaining temple as a final back-up plan to return.
- Ignored Expert: Beast warns Cortez that Apocalypse will betray him when it's most convenient. He doesn't listen and suffers for it.
- The Power of Friendship: Seeing a picture of the team and one of him and Jubilee cause Feral!Beast to regain some self-control.
- Retcon: Caliban is mentioned as having been a Morlock, even though he had just appeared in cameos as a background mutant character but never among the assembled Morlocks.
- Something We Forgot: The episode is built on tying off a major loose end from the "Sanctuary" two-parter. Cortez was shown being rescued from Asteroid M by Apocalypse, but he did not go on to appear in the "Beyond Good and Evil" four-parter. This episode explains what he's been up to in all that time.
- Superpowered Evil Side: Cortez uses his enhanced powers to turn Beast into a mostly feral monster.
- This Cannot Be!: Beast's reaction to seeing Cortez is still alive.
- Token Good Teammate: Caliban to the Hounds.
- Undying Loyalty: Unlike the time he served Magneto, Cortez is unfailingly loyal to Apocalypse.
- You Have Failed Me: "But you have provided me with a vessel, Cortez."
